Table 1.

Summary of the clinical presentation, imaging findings and treatment of focal nodular marrow hyperplasia (FNMH) in the current literature

Reference	Patient details	Presentation	Imaging	Subsequent investigations and treatment
Bordalo-Rodrigues et al6	77 M	Lung cancer, underwent whole body FDG PET for staging.	PET CT-T8 vertebral body uptake. MRI- 2×2 cm low T1 lesion in T8 (but higher than disk signal). Not seen on T2 FS.	CT-guided T8 biopsy showed FNMH. Pulmonary lesion alone resected.
Pui et al7	37 M	Left proximal tibial osteosarcoma. Patient had further knee pain following preoperative chemotherapy	MRI - new 2 cm oval lesion in left mid-femur. Lesion isointense to muscle on T1 and T2 FS images. CT-focal intramedullary sclerosis with no corresponding bone scan uptake.	Patient refused biopsy of mid-femur lesion. High above knee amputation of primary tumour and femoral lesion. Histology of the latter revealed FNMH.
Chow et al8	14 M	Pain and swelling left proximal tibia.	Osteosarcoma left proximal tibia. MRI-possible skip metastasis 7 cm below tumour in anterior tibial cortex. Isointense to muscle T1, high T2 FS SI. CT-no lesion. Bone scan-no uptake.	Tumour excision including distal tibial lesion had chemotherapy followed by left total knee replacement. Histology of distal lesion confirmed FNMH.
	7 M	Left distal thigh pain	MRI-left distal femoral osteosarcoma. Possible skip metastasis in left proximal femur. MRI-hyperintense to muscle T1, hyperintense T2FS, mild post-gad enhancement. PET CT-no uptake. Bone scan-normal.	Proximal femur biopsy showed FNMH. Patient has segmental resection excluding proximal lesion.
	17 M	Right knee pain for 3 months.	Right distal femoral osteosarcoma. Bone scan- uptake in T10 and right lesser trochanter. MRI- low T1, high T2 FS lesions. CT-Faint T10 sclerosis. All thought to be metastases.	Right total knee replacement. Lesser trochanter lesion excised. T10 lesion excised with bone graft and spinal fusion. Both showed FNMH.
	14 M	Right thigh swelling 1 month.	Osteosarcoma right femoral diaphysis. MRI-further proximal femoral lesion, no mention of MRI features.	Biopsy of proximal femoral lesion-FNMH. Had chemotherapy followed by limb salvage surgery.
	42 M	Left femur subtrochanteric fracture after trivial injury.	PET-CT showed uptake at fracture site with marrow infiltration-Ewing sarcoma. Also showed uptake in mid-femur. MRI-not described. Bone scan-normal.	Had segmental resection including mid-femoral lesion. Histology of latter-FNMH.
Shigematsu et al9	Eight males (average age 64) all with vertebral body lesions. Only one was localised.	Six patients had known malignancy but were asymptomatic; two had low back pain; five thoracic spine location; three lumbar spine location.	All eight vertebral body lesions suspicious for metastases on MRI. All were hypointense to marrow on T1 and T2. 3/4 hyperintense and 1/4 isointense on STIR. All eight lesions had higher than normal SUV max on FDG PET CT (range 2.09–3.06). 5/8 showed no uptake on bone scan. 7/8 showed subtle high attenuation on CT compared to normal marrow.	All eight cases diagnosed as hyperplastic haematopoietic bone marrow (HHBM) following CT biopsy.
Tanaka et al10	66 M	Ca oesophagus	L3 vertebral body lesion. Low SI on T1W and T2W. Increased activity on FDG-PET	CT-guided biopsy revealed hypercellular marrow.
Yasuda et al11	63 M	Ca oesophagus	FDG-PET showed lesions in sternum and sacrum. MRI showed low SI on T1 and T2W sequences.	Biopsy of sternum revealed bone marrow hyperplasia.